1. Field of the Invention
The present invention relates to a method of forming a laminated body by laminating a ceramics green sheet, and more specifically, to a method of forming a laminated body preferable for manufacturing a gas sensor for measuring a predetermined gas concentration in a measurement gas.
2. Description of the Background Art
Conventionally, various measuring devices have been used for determining a concentration of a desired gas component in a measurement gas. A known device of measuring a NOx concentration in a measurement gas such as a combustion gas, for example, is a sensor having a Pt-containing electrode and a Rh-containing electrode formed on an oxygen ion conductive solid electrolyte, such as zirconia (ZrO2) (see Japanese Patent Application Laid-Open No. 8-271476 and Japanese Patent Application Laid-Open No. 2004-37473, for example).
A gas sensor as recited in Japanese Patent Application Laid-Open No. 8-271476 or Japanese Patent Application Laid-Open No. 2004-37473 is manufactured by cutting and burning a laminated body formed by laminating and integrating a plurality of ceramics green sheets (hereinafter also referred to as merely “green sheets”) including zirconia, which is an oxygen ion conductive solid electrolyte, as a ceramics component, a predetermined circuit pattern (hereinafter also referred to as merely a “pattern”) being formed on each of the plurality of ceramics green sheets.
The circuit pattern is formed by a printing method using a predetermined printing paste. When laminating a plurality of relatively thick green sheets with a thickness of a few hundred μm, the plurality of green sheets may be laminated with a bonding paste printed (applied) previously thereon. As a result, printing (and drying thereafter) may be performed more than once on a green sheet composing each layer of the laminated body. The green sheet is normally deformed every time printing is done. Thus the problem arises that the layered accuracy is lowered if using the green sheet on which printing is performed many times (allowing laminating failure exceeding the acceptable range), causing the yield deterioration in manufacturing a gas sensor or the like.
The laminated green sheet is integrated by heating and applying a pressure with an oil-hydraulic press, where an establishment of conditions is needed to laminate with high accuracy and stability.